Maintaining uniform tension in yarn being fed to machines utilized in the manufacturing of textile products has long been an important factor effecting the productivity of the manufacturing process and the quality of the textile product produced. Variations in yarn tension can result in undesirable variations in the product produced with the yarn, thereby effecting the quality of the product. In severe cases, the product or portions of the product may not be usable or the equipment may be stopped because of a wide tension variation.
Many attempts have been made to control yarn tension so that a relatively uniform yarn tension is present in the yarn when it is fed to a yarn processing machine. The best of these has proven to be ball-type yarn tensioning units, such as disclosed in Zollinger U.S. Reissue Pat. No. RE.31,024 and in Zollinger U.S. Pat. No. 5,820,050. In a particularly effective system, specially applicable to maintain uniform tension when feeding relatively large size yarns at moderate speeds, is a combination of the ball-type yarn tension units disclosed in the aforesaid patents. An arrangement such as this is illustrated in FIG. 1, which illustrates the two ball-type yarn tensioning units mounted on a frame at a generally horizontal spacing with yarn being fed upwardly from a package through the ball-type yarn tensioning unit of the aforesaid U.S. Pat. No. 5,820,050 and from that unit across the space between the units and into and down through a ball-type yarn tension unit of the type disclosed in U.S. Reissue Pat. No. RE.31,024, from which the yarn exits to a textile machine, such as a cabler.